Microanatomy of the acetabular cavity and its relation to growth

The anatomy and development of the growing acetabulum are not clearly under stood, We dissected and studied histologically two acetabula from the pelvi s of a three-month-old infant, Relative rates of growth at the different gr owth plates were assessed by comparing the height of the proliferative laye r with that of the hypertrophic layer. The three bones which form the acetabulum are surrounded by growth plates o n all sides except medially. These face towards the centre of the triradiat e cartilage, the limbs of the triradiate cartilage and the articular surfac e and each may be divided into four distinct areas according to the orienta tion of its cell columns which reflect the direction of growth. Growth was particularly rapid at the ischial growth plates directed towards the centre and the articular cartilage, and on both sides of the anterior limb of the triradiate cartilage. These findings mag explain the mechanism by which the acetabulum changes orientation and inclination with growth.